Why is the walk cycle not working?
It looks like your character is moving forwards both in Pose mode and in Object mode. I guess it's your problem.

Most of the time, when you create a repetitive walk cycle in Pose mode, you'll make your character (i.e. his root bone) stand "still" on the X and Y axis, like if he was walking on a treadmill. It's only once in Object mode that you'll make the whole armature move forwards, either with a Follow Path constraint or just making him move from point A to point B with keyframes.

It's the combination of treadmill animation and movement in the scene that will recreate the illusion of walk.

Making an armature move forwards in Pose mode (i.e. moving its root bone or moving the other bones away from the root bone) is only useful for small moves through the scene, or for some complex and non-repetitive movements, and in that case you generally won't make him move in Object mode.